In this study, we find combination of building materials and construction methods to reduce environmental loads (LCCO_2, final waste, LCC) with using genetic algorithms system which is developped to select those combination. We apply the system to "the standard building model (often used at calculating thermal load)", and search combinations to minimize each value through life cycle. Then we can find combinations to reduce a11 values at the same time by the system using "restriction method". Each value is much less than each of house which has enough thermal insulating material to satisfy "standard by energy conservation next generation".
